Imidazolone as an Amide Bioisostere in the Development of β-1,3-N-Acetylglucosaminyltransferase 2 (B3GNT2) Inhibitors

B3GNT2 is responsible for elongation of cell surface long-chain polylactosamine, which influences the regulation of the immune response, making it an attractive target for immunomodulation. In the development of amide containing B3GNT2 inhibitors guided by structure-based drug design, imidazolones were found to successfully serve as amide bioisosteres. This novel imidazolone isosteric strategy alleviated torsional strain of the amide bond on binding to B3GNT2 and improved potency, isoform selectivity, as well as certain physicochemical and pharmacokinetic properties. Herein, we present the synthesis, SAR, X-ray cocrystal structures, and in vivo PK properties of imidazol-4-ones in the context of B3GNT2 inhibition.

Potent GCN2 Inhibitor Capable of Reversing MDSC-Driven T Cell Suppression Demonstrates In Vivo Efficacy as a Single Agent and in Combination with Anti-Angiogenesis Therapy

General control nonderepressible 2 (GCN2) protein kinase is a cellular stress sensor within the tumor microenvironment (TME), whose signaling cascade has been proposed to contribute to immune escape in tumors. Herein, we report the discovery of cell-potent GCN2 inhibitors with excellent selectivity against its closely related Integrated Stress Response (ISR) family members heme-regulated inhibitor kinase (HRI), protein kinase R (PKR), and (PKR)-like endoplasmic reticulum kinase (PERK), as well as good kinome-wide selectivity and favorable PK. In mice, compound 39 engages GCN2 at levels ≥80% with an oral dose of 15 mg/kg BID. We also demonstrate the ability of compound 39 to alleviate MDSC-related T cell suppression and restore T cell proliferation, similar to the effect seen in MDSCs from GCN2 knockout mice. In the LL2 syngeneic mouse model, compound 39 demonstrates significant tumor growth inhibition (TGI) as a single agent. Furthermore, TGI mediated by anti-VEGFR was enhanced by treatment with compound 39 demonstrating the complementarity of these two mechanisms.

EBV+ tumors exploit tumor cell-intrinsic and -extrinsic mechanisms to produce regulatory T cell-recruiting chemokines CCL17 and CCL22

The Epstein-Barr Virus (EBV) is involved in the etiology of multiple hematologic and epithelial human cancers. EBV+ tumors employ multiple immune escape mechanisms, including the recruitment of immunosuppressive regulatory T cells (Treg). Here, we show some EBV+ tumor cells express high levels of the chemokines CCL17 and CCL22 both in vitro and in vivo and that this expression mirrors the expression levels of expression of the EBV LMP1 gene in vitro. Patient samples from lymphoblastic (Hodgkin lymphoma) and epithelial (nasopharyngeal carcinoma; NPC) EBV+ tumors revealed CCL17 and CCL22 expression of both tumor cell-intrinsic and -extrinsic origin, depending on tumor type. NPCs grown as mouse xenografts likewise showed both mechanisms of chemokine production. Single cell RNA-sequencing revealed in vivo tumor cell-intrinsic CCL17 and CCL22 expression combined with expression from infiltrating classical resident and migratory dendritic cells in a CT26 colon cancer mouse tumor engineered to express LMP1. These data suggest that EBV-driven tumors employ dual mechanisms for CCL17 and CCL22 production. Importantly, both in vitro and in vivo Treg migration was effectively blocked by a novel, small molecule antagonist of CCR4, CCR4-351. Antagonism of the CCR4 receptor may thus be an effective means of activating the immune response against a wide spectrum of EBV+ tumors.

Tumors establish resistance to immunotherapy by regulating Treg recruitment via CCR4

BACKGROUND

Checkpoint inhibitors (CPIs) such as anti-PD(L)-1 and anti-CTLA-4 antibodies have resulted in unprecedented rates of antitumor responses and extension of survival of patients with a variety of cancers. But some patients fail to respond or initially respond but later relapse as they develop resistance to immune therapy. One of the tumor-extrinsic mechanisms for resistance to immune therapy is the accumulation of regulatory T cells (T_reg) in tumors. In preclinical and clinical studies, it has been suggested that tumor trafficking of T_reg is mediated by CC chemokine receptor 4 (CCR4). Over 90% of human T_reg express CCR4 and migrate toward CCL17 and CCL22, two major CCR4 ligands that are either high at baseline or upregulated in tumors on CPI treatment. Hence, CCR4 antagonism has the potential to be an effective antitumor treatment by reducing the accumulation of T_reg into the tumor microenvironment (TME).

METHODS

We developed in vitro and in vivo models to assess T_reg migration and antitumor efficacy using a potent and selective CCR4 antagonist, CCR4-351. We used two separate tumor models, Pan02 and CT26 mouse tumors, that have high and low CCR4 ligand expression, respectively. Tumor growth inhibition as well as the frequency of tumor-infiltrating T_reg and effector T cells was assessed following the treatment with CCR4 antagonist alone or in combination with CPI.

RESULTS

Using a selective and highly potent, novel small molecule inhibitor of CCR4, we demonstrate that migration of CCR4⁺ T_reg into the tumor drives tumor progression and resistance to CPI treatment. In tumor models with high baseline levels of CCR4 ligands, blockade of CCR4 reduced the number of T_reg and enhanced antitumor immune activity. Notably, in tumor models with low baseline level of CCR4 ligands, treatment with immune CPIs resulted in significant increases of CCR4 ligands and T_reg numbers. Inhibition of CCR4 reduced T_reg frequency and potentiated the antitumor effects of CPIs.

CONCLUSION

Taken together, we demonstrate that CCR4-dependent T_reg recruitment into the tumor is an important tumor-extrinsic mechanism for immune resistance. Blockade of CCR4 led to reduced frequency of T_reg and resulted in increased antitumor activity, supporting the clinical development of CCR4 inhibitors in combination with CPI for the treatment of cancer.

STATEMENT OF SIGNIFICANCE

CPI upregulates CCL17 and CCL22 expression in tumors and increases T_reg migration into the TME. Pharmacological antagonism of the CCR4 receptor effectively inhibits T_reg recruitment and results in enhanced antitumor efficacy either as single agent in CCR4 ligand^high tumors or in combination with CPIs in CCR4 ligand^low tumors.

Scalable Total Synthesis, IP3R Inhibitory Activity of Desmethylxestospongin B, and Effect on Mitochondrial Function and Cancer Cell Survival

The scalable synthesis of the oxaquinolizidine marine natural product desmethylxestospongin B is based on the early application of Ireland-Claisen rearrangement, macrolactamization, and a late-stage installation of the oxaquinolizidine units by lactam reduction. The synthesis serves as the source of material to investigate calcium signaling and its effect on mitochondrial metabolism in various cell types, including cancer cells.

Novel Piperidinyl-Azetidines as Potent and Selective CCR4 Antagonists Elicit Antitumor Response as a Single Agent and in Combination with Checkpoint Inhibitors

The C-C chemokine receptor 4 (CCR4) is broadly expressed on regulatory T cells (T_reg) as well as other circulating and tissue-resident T cells. T_reg can be recruited to the tumor microenvironment (TME) through the C-C chemokines CCL17 and CCL22. T_reg accumulation in the TME has been shown to dampen the antitumor immune response and is thought to be an important driver in tumor immune evasion. Preclinical and clinical data suggest that reducing the T_reg population in the TME can potentiate the antitumor immune response of checkpoint inhibitors. We have developed small-molecule antagonists of CCR4, featuring a novel piperidinyl-azetidine motif, that inhibit the recruitment of T_reg into the TME and elicit antitumor responses as a single agent or in combination with an immune checkpoint blockade. The discovery of these potent, selective, and orally bioavailable CCR4 antagonists, and their activity in in vitro and in vivo models, is described herein.

Lithium Enolates in the Enantioselective Construction of Tetrasubstituted Carbon Centers with Chiral Lithium Amides as Noncovalent Stereodirecting Auxiliaries

Lithium enolates derived from carboxylic acids are ubiquitous intermediates in organic synthesis. Asymmetric transformations with these intermediates, a central goal of organic synthesis, are typically carried out with covalently attached chiral auxiliaries. An alternative approach is to utilize chiral reagents that form discrete, well-defined aggregates with lithium enolates, providing a chiral environment conducive of asymmetric bond formation. These reagents effectively act as noncovalent, or traceless, chiral auxiliaries. Lithium amides are an obvious choice for such reagents as they are known to form mixed aggregates with lithium enolates. We demonstrate here that mixed aggregates can effect highly enantioselective transformations of lithium enolates in several classes of reactions, most notably in transformations forming tetrasubstituted and quaternary carbon centers. Easy recovery of the chiral reagent by aqueous extraction is another practical advantage of this one-step protocol. Crystallographic, spectroscopic, and computational studies of the central reactive aggregate, which provide insight into the origins of selectivity, are also reported.

10-Step Asymmetric Total Synthesis and Stereochemical Elucidation of (+)-Dragmacidin D

The asymmetric synthesis of dragmacidin D (1) was completed in 10 steps. Its sole stereocenter was set by using direct asymmetric alkylation enabled by a C2-symmetric tetramine and lithium N-(trimethylsilyl)-tert-butylamide as the enolization reagent. A central Larock indole synthesis was employed in a convergent assembly of the heterocyclic subunits. The stereochemical evidence from this work strongly supports the predicted S configuration at the 6''' position, which is consistent with other members of the dragmacidin family of natural products.

Direct enantioselective conjugate addition of carboxylic acids with chiral lithium amides as traceless auxiliaries

Michael addition is a premier synthetic method for carbon-carbon and carbon-heteroatom bond formation. Using chiral dilithium amides as traceless auxiliaries, we report the direct enantioselective Michael addition of carboxylic acids. A free carboxyl group in the product provides versatility for further functionalization, and the chiral reagent can be readily recovered by extraction with aqueous acid. The method has been applied in the enantioselective total synthesis of the purported structure of pulveraven B.

Enantioselective synthesis of tatanans A-C and reinvestigation of their glucokinase-activating properties

The tatanans are members of a novel class of complex sesquilignan natural products recently isolated from the rhizomes of Acorus tatarinowii Schott plants. Tatanans A, B and C have previously been reported to have potent glucokinase-activating properties that exceed the in vitro activity of known synthetic antidiabetic agents. Here, using a series of sequential [3,3]-sigmatropic rearrangements, we report the total synthesis of tatanan A in 13 steps and 13% overall yield. We also complete a concise enantioselective total synthesis of more complex, atropisomeric tatanans B and C via a distinct convergent strategy based on a palladium-catalysed diastereotopic aromatic group differentiation (12 steps, 4% and 8% overall yield, respectively). A plausible biosynthetic relationship between acyclic tatanan A and spirocyclic tatanans B and C is proposed and probed experimentally. With sufficient quantities of the natural products in hand, we undertake a detailed functional characterization of the biological activities of tatanans A-C. Contrary to previous reports, our assays utilizing pure recombinant human enzyme demonstrate that tatanans do not function as allosteric activators of glucokinase.

Stability of cyclic imine toxins: interconversion of pinnatoxin amino ketone and pinnatoxin A in aqueous media

Pinnatoxins belong to the cyclic imine (CI) group of marine toxins with a unique toxicological profile. The need for structural integrity of the aliphatic 7-membered cyclic imine for the potent bioactivity of pinnatoxins has been experimentally demonstrated. In this study, we probe interconversion of the natural cyclic imine and its open form, pinnatoxin A amino ketone (PnTX AK), under physiologically relevant aqueous conditions. Our studies demonstrate the high stability of PnTX A. The unusual stability of the imine ring in PnTX A has implications for its oral toxicity and detoxification. These studies, as well the access to PnTX amino ketone, were enabled by the total synthesis of (+)-pinnatoxin A completed previously in our laboratory.

Effects of Crop Residue on the Persistence of Steinernema carpocapsae

We determined the effects of crop residue on the persistence of an entomopathogenic nematode, Steinernema carpocapsae. During 2 consecutive years, nematodes were applied at rates of 2.5 x 10 and 1.0 x 10 infective juveniles/m(2) to small field plots planted with corn. Nematode persistence was monitored by exposing Galleria mellonella larvae to soil samples from plots with and without crop residue (approximately 75% coverage of soybean stubble). Persistence of S. carpocapsae was significantly greater in crop residue plots than in plots without residue. In crop residue plots that received the higher rate of nematode application, larval mortality did not significantly decrease during the study period (3 to 5 days) and remained above 85%. In nematode-treated plots without crop residue, however, larval mortality fell from over 96% to below 11% and 35% in the first and second trials, respectively. The increased crop residue may have benefited nematode persistence through protection from desiccation or ultraviolet light. We conclude that increased ground cover in cropping systems (e.g., due to reduced tillage) may lead to increased insect pest suppression with entomopathogenic nematodes.

Effects of antibiotic therapy on Pseudomonas aeruginosa-induced lung injury in a rat model

The effect of antibiotics on the acute lung injury induced by virulent Pseudomonas aeruginosa PA103 was quantitatively analyzed in a rat model. Lung injury was induced by the instillation of PA103 directly into the right lower lobes of the lungs of anesthetized rats. The alveolar epithelial injury, extravascular lung water, and total plasma equivalents were measured as separate, independent parameters of acute lung injury. Four hours after the instillation of PA103, all the parameters were increased linearly depending on the dose of P. aeruginosa. Next, we examined the effects of intravenously administered antibiotics on the parameters of acute lung injury in D-galactosamine-sensitized rats. One hour after the rats received 10(7) CFU of PA103, an intravenous bolus injection of aztreonam (60 mg/kg) or imipenem-cilastatin (30 mg/kg) was administered. Despite an MIC indicating resistance, imipenem-cilastatin improved all the measurements of lung injury; in contrast, aztreonam, which had an MIC indicating sensitivity, did not improve any of the lung injury parameters. The antibiotics did not generate different quantities of plasma endotoxin; therefore, endotoxin did not appear to explain the differences in lung injury. This in vivo model is useful to quantitatively compare the efficacies of parenteral antibiotic administration on Pseudomonas airspace infections.

Reduced immunotoxicity and preservation of antibacterial activity in a releasable side-chain carbapenem antibiotic

A carbapenem antibiotic, L-786,392, was designed so that the side chain that provides high-affinity binding to the penicillin-binding proteins responsible for bacterial resistance was also the structural basis for ameliorating immunopathology. Expulsion of the side chain upon opening of the beta-lactam ring retained antibacterial activity while safely expelling the immunodominant epitope. L-786,392 was well tolerated in animal safety studies and had significant in vitro and in vivo activities against methicillin- and vancomycin-resistant Staphylococci and vancomycin-resistant Enterococci.

In vivo activity and pharmacokinetic evaluation of a novel long-acting carbapenem antibiotic, MK-826 (L-749,345)

MK-826 (formerly L-749,345), is a potent 1-beta-methyl carbapenem with a long half-life and broad spectrum of activity. This compound is presently in phase-II clinical trials. Its activity against a number of gram-positive and gram-negative organisms was compared to those of imipenem (IPM) and eight other beta-lactam agents in two in vivo murine infection models. The distribution in tissue and pharmacokinetic properties of MK-826 and ceftriaxone (CTRX) were also evaluated in CD-1 mice following a single intraperitoneal dose (10 mg/kg of body weight). In addition, concentrations in plasma as well as biliary and urinary recovery of MK-826 were compared to that of CTRX in a cannulated rat model. In a localized murine thigh infection model, MK-826 and IPM were superior to a variety of beta-lactam antibiotics in reduction of Staphylococcus aureus CFU compared with results from nontreated controls (eliminating >/=4 log10 CFU). Similar activities of IPM and MK-826 were observed in a gram-positive bacterial murine systemic infection model. While IPM demonstrated greater efficacy than MK-826 against Enterobacter cloacae (50% effective doses [ED50s] of 0.062 and 0.227 mg/kg, respectively) and Pseudomonas aeruginosa (ED50s of 0.142 and 3.0 mg/kg, respectively) systemic infections, MK-826 was 8- to 350-fold more efficacious than IPM against all other gram-negative organisms in this infection model. In mice, MK-826 demonstrated a higher peak concentration in serum (62.8 versus 42.6 microg/ml) and a larger area under the curve (AUC) (150.8 versus 90.0 microg . hr/ml) than CTRX. The concentrations of MK-826 and CTRX in serum declined slowly, with levels of 3.6 and 2.0 microg/ml remaining, respectively, at 6 h posttreatment. The rat pharmacokinetic model showed the average AUC of MK-826 to be greater than that of CTRX (284 versus 142 microg . hr/ml) following a single 10-mg/kg dose. Also, a half-life of MK-826 longer than that of CTRX (3.2 versus 2.3 h) was observed in this species. The total amount of drug excreted in the bile in 8 h was greater for CTRX (55 to 64% of the dose) than for MK-826 (6 to 12.5% of the dose). Urinary recovery was similar for both antibiotics, with 16 to 18% of the dose recovered over an 8-h period. This excellent broad-spectrum in vivo efficacy of MK-826, together with advantageous pharmacokinetics, supports the argument for its further clinical development.

Interaction of insecticides, entomopathogenic nematodes, and larvae of the western corn rootworm (Coleoptera: Chrysomelidae)

Chemical insecticides and entomopathogenic nematodes have been independently used to suppress corn rootworm damage in maize. We report on the mortality response of larvae of the western corn rootworm, Diabrotica virgifera virgifera LeConte, to the combined treatment with 1 of 3 insecticides (terbufos, fonofos, and tefluthrin) and the entomopathogenic nematode Steinernema carpocapsae Weiser (Mexican strain). Corn rootworm mortality with combinations of the insecticides terbufos or fonofos and S. carpocapsae was typically additive for the 2 agents. Evidence of antagonism between these agents was sometimes observed. The combination of tefluthrin with S. carpocapsae frequently resulted in a synergistic response and a 24% average increase in expected mortality. The influence of the tefluthrin appears to be isolated to an effect on the rootworm larvae. Synergism also was observed when tefluthrin was combined with the nematode Heterorhabditis bacteriophora Poinar (Lewiston strain). The combined use of tefluthrin with an entomopathogenic nematode may offer an integrated approach to increase the efficacy of entomopathogenic nematodes for insect control.

The role of Wolbachia bacteria in reproductive incompatibilities and hybrid zones of Diabrotica beetles and Gryllus crickets

A rickettsial bacterium in the genus Wolbachia is the cause of a unidirectional reproductive incompatibility observed between two major beetle pests of maize, the western corn rootworm, Diabrotica virgifera virgifera, and the Mexican corn rootworm, D. v. zeae. These subspecies are allopatric except for two known regions of sympatry in Texas and Mexico. We demonstrate that populations of D. v. virgifera, with the exception of two populations in southern Arizona, are infected with a strain of Wolbachia. Populations of D. v. zeae are not infected. Treatment of D. v. virgifera with tetracycline eliminated the Wolbachia and removed the reproductive incompatibility. Similar patterns of reproductive incompatibility exist among taxa of the cricket genus Gryllus. Gryllus assimilis, G. integer, G. ovisopis, G. pennsylvanicus, and G. rubens are infected with Wolbachia whereas G. firmus is usually not. Populations of G. rubens and G. ovisopis carry the same Wolbachia strain, which is distinct from that of G. integer. G. pennsylvanicus is infected with two Wolbachia strains, that found in G. rubens and one unique to G. pennsylvanicus. Moreover, a proportion of G. pennsylvanicus individuals harbors both strains. Wolbachia may have influenced speciation in some members of the genus Gryllus by affecting the degree of hybridization between species. Given that Wolbachia infections are relatively common in insects, it is likely that other insect hybrid zones may be influenced by infections with Wolbachia.

Effects of tacrine (THA) on spatial reference memory and cholinergic enzymes in specific rat brain regions

Cognitive function of rats treated with saline (control), THA (8 mg/kg, i.p.), scopolamine (5 mg/kg, i.p.), or a combination of THA (8 mg/kg) and scopolamine (5 mg/kg) was tested in the Morris water maze. The latency to find the platform in the water maze was used to evaluate performance. THA did not significantly alter the latency period as compared to control rats. Scopolamine resulted in a highly significant (p<0.01) increase in latency period (183% increase) as compared to saline treated controls. However, when THA was concurrently administered with scopolamine, it was able to completely reverse the performance decrement induced by scopolamine. Immediately following spatial reference memory testing, animals were sacrificed by decapitation one hour post injection. Brains were immediately removed and the cortex, hippocampus, hypothalamus, and pituitary were dissected and their choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activity were determined spectrophotometrically. THA administration resulted in a significant increase in ChAT activity in the cortex (23% increase). However, when THA was concurrently administered with scopolamine, a significant increase in ChAT activity was observed in cortex (77% increase), hippocampus (32% increase), hypothalamus (97% increase), and pituitary (92.5% increase). THA administration resulted in a significant decrease in AChE activity (p<0.001) in cortex (62% decrease), hippocampus (78% decrease), and hypothalamus (90% decrease). When tacrine was administered with scopolamine, a significant increase was found in the cortex (197% increase) and the hippocampus (207% increase). In conclusion, the increase in ChAT activity produced by tacrine may in part explain its ability to reverse the scopolamine induced decrease in spatial reference memory and may play a role in its beneficial effect in improving cognitive ability.

Parasitism of Western Corn Rootworm Larvae and Pupae by Steinernema carpocapsae

Virulence and development of the insect-parasitic nematode, Steinernema carpocapsae (Weiser) (Mexican strain), were evaluated for the immature stages of the western corn rootworm, Diabrotica virgifera virgifera LeConte. Third instar rootworm larvae were five times more susceptible to nematode infection than second instar larvae and 75 times more susceptible than first instar larvae and pupae, based on laboratory bioassays. Rootworm eggs were not susceptible. Nematode development was observed in all susceptible rootworm stages, but a complete life cycle was observed only in second and third instar larvae and pupae. Nematode size was affected by rootworm stage; the smallest infective-stage nematodes were recovered from second instar rootworm larvae. Results of this study suggest that S. carpocapsae should be applied when second and third instar rootworm larvae are predominant in the field.

Allergic reactions to polidocanol for vein sclerosis. Two case reports

BACKGROUND

Polidocanol is a sclerosing solution that is highly valued by clinicians and patients for its painlessness, high efficacy, excellent safety profile, low incidence of side effects, and for the rarity of its allergic reactions. Previous estimates of the incidence of allergic reactions have ranged from 0 to 0.06%.

OBJECTIVE

Improved recognition of systemic allergy to polidocanol is desirable for both clinicians and for patients. We have attempted to describe two cases recently observed in our population and to provide an improved upper-bounds estimate for the true population incidence of allergy to polidocanol.

RESULTS

We report two recent cases of mild systemic allergic reaction to polidocanol in a population of 689 exposed patients, for an observed incidence of 0.3% in our patient population. We have calculated a 95% confidence upper-bound estimate of 0.91% for the incidence of polidocanol allergy in the general population.

CONCLUSION

Allergy to polidocanol may be more common than previously recognized. Careful questioning of previously treated patients and more prolonged observation of patients after treatment may yield a larger number of recognized cases.

beta-Lactam antibiotic-induced release of free endotoxin: in vitro comparison of penicillin-binding protein (PBP) 2-specific imipenem and PBP 3-specific ceftazidime

The relative effects of two beta-lactam antibiotics, penicillin-binding protein (PBP) 2-specific imipenem and PBP 3-specific ceftazidime, upon in vitro induction of lipopolysaccharide (LPS) release were investigated against smooth- and rough-LPS mutant isolates of Pseudomonas aeruginosa. Free LPS liberated from both isolates are 10- to 40-fold higher for ceftazidime-exposed cultures than control or imipenem-treated cultures after 4-8 h at 35 degrees C despite equivalent MICs. Lethalities of filtrates in mice correlated with in vitro endotoxin assay results. Sub-MIC levels of ceftazidime induced filamentation and LPS release without significant bacterial lysis. Amounts released not only matched the quantities achieved at inhibitory concentrations (e.g., 1-, 2-, and 50-times MIC) of ceftazidime but significantly exceeded levels of LPS liberated by exposure to imipenem, less than or equal to 100 times its MIC. Sub-MIC levels of imipenem released relatively small amounts of free LPS while reducing colony counts approximately 2 logs more than equivalent amounts of ceftazidime after 2 h. Data suggest that ceftazidime-induced filamentation releases larger quantities of bioreactive LPS than nonfilamentous fast-lysing imipenem.

Further examination of the equity sensitivity construct

This study was conducted to investigate whether a measure of equity sensitivity can predict individual reactions to inequity. The equity sensitivity construct suggests that there are three categories of individual preferences for equity: (1) benevolent individuals prefer their input:outcome ratios be less than those of their comparison others, (2) equity sensitive individuals prefer their input:outcome ratios be equal to those of comparison others, and (3) entitled individuals prefer their input:outcome ratios be higher than those of comparison others. To identify their appropriate equity sensitivity category, 639 undergraduate students and 119 fast-food restaurant employees were administered the Equity Sensitivity Instrument. These subjects were then asked to react to two underreward/overreward scenarios. Analysis indicates that equity sensitivity groups generally exhibit reactions in the direction predicted by the study; however, some inconsistencies require further study. Research should examine why some reactions to inequity are chosen over others and how the longitudinal effects of a work relationship may influence one's reactions to inequity.

Glycolipids as host resistance stimulators

6-(5-Cholesten-3 beta-yloxy)hexyl 1-thio-beta-D-mannopyranoside (L-644,257) enhances natural host resistance in cyclophosphamide-treated mice against Pseudomonas aeruginosa in a dose-dependent manner. It is active sc, im, and ip but not orally. L-644,257 is substantially more protective against P. aeruginosa than its alpha anomer. The beta-L-fucose glycolipid is more effective when given im and ip than sc. The lactose and beta-D-glucose glycolipids were only marginally effective to nonprotective. The 17 beta-steroidal side chain of L-644,257 can be modified without substantial loss of protective activity.

Steroidal glycolipid, L-644,257, is a potent enhancer of nonspecific host resistance

A steroidal glycolipid that enhances the nonspecific cellular response to opportunistic infection in an immunocompromised host has been discovered. A dose dependent response with 6-(5-cholesten-3 beta-yloxy)hexyl 1-thio-beta-D-mannopyranoside, L-644,257, was observed against several infective agents including bacterial, fungal, and viral pathogens in cyclophosphamide-treated mice. A mechanism for this protective action is proposed.

Human monoclonal antibodies that protect mice against challenge with Pseudomonas aeruginosa

Lymphocytes from healthy volunteers and from cystic fibrosis patients were transformed with Epstein-Barr virus and cultured at a limiting dilution to generate lymphoblastoid cell lines that secreted human monoclonal antibodies specific for lipopolysaccharide (LPS) from Pseudomonas aeruginosa. Three cell lines (RM5, FDD7, and 11F9) produced immunoglobulin M (IgM) antibody species that reacted specifically with P. aeruginosa Fisher immunotypes 2, 4, and 5, respectively, and with LPS extracted from these immunotypes. A fourth cell line (9H10) produced a single IgM antibody species that recognized P. aeruginosa immunotypes 3, 6, and 7 and LPS extracted from them. Monoclonal antibodies secreted by cell lines RM5, FDD7, and 11F9 protected neutropenic mice prophylactically against challenge with P. aeruginosa immunotypes 2, 4, and 5, and those secreted by 9H10 protected against P. aeruginosa immunotypes 3 and 6 but did not protect against immunotype 7. In vivo experiments indicated that antibodies protected mice against infection by increasing the rate of bacterial clearance.

X-linked immunodeficient mice as a model for testing the protective efficacy of monoclonal antibodies against Pseudomonas aeruginosa

(DBA/N[female] X CBA/2[male])F1 males have been reported to be deficient in producing antibodies against a number of antigens, including carbohydrates (I. Scher, Adv. Immunol. 35:1-71, 1982). We show that F1 male mice, in contrast to females, made less lipopolysaccharide (LPS)-specific antibodies after immunization with heat-inactivated Pseudomonas aeruginosa and had significantly less naturally occurring LPS-specific antibodies. Furthermore, neutropenic males were 50 to 1,000 times more sensitive to challenge with representative isolates belonging to the seven Fisher immunotypes. Administration to neutropenic F1 males of a human monoclonal antibody specific for the O carbohydrates of P. aeruginosa immunotype 2 LPS or administration of serum from rabbits immunized with heat-inactivated P. aeruginosa immunotype 1 raised the level of resistance to bacterial challenge close to that of females. The results show that the X-linked immunodeficient mouse is an excellent model with which to test the protective efficacy of P. aeruginosa-specific monoclonal antibodies.

System for continuous monitoring of point defect concentrations during irradiations and anneals

An integrated system, cryostat, electronics, and computer used for detailed resistivity measurements during low-temperature irradiations and anneals of metals is described. The thermal response time and rate of heat removal from the specimens are optimized. The system has excellent stability for extended isothermal anneals; measurements of deviations from Mathiessen's rule are discussed to illustrate this feature. Examples are given of the use of the system to determine dense sets of thermal activation energies during anneals through state I. These determinations are made by linear heating at different rates during recombinations of close Frenkel pairs, and by abruptly and repeatedly changing the annealing temperature during the recovery of more widely separated pairs.

Epidemic gastritis with hypochlorhydria

Seventeen of 37 healthy volunteers participating in studies of acid secretion and 1 patient with Zollinger-Ellison syndrome became rapidly and profoundly hypochlorhydric. A mild illness with epigastric pain occurred in 9 subjects, usually several days before detection of hypochlorhydria. Gastric mucosal biopsy specimens taken from subjects during hypochlorhydria revealed severe fundal and antral gastritis; however, even when acid secretion was severely depressed, parietal cells were abundant and appeared normal histologically. During hypochlorhydria, gastric permeability to hydrogen, sodium, and lithium was normal in 4 subjects. Serum gastrin concentrations were usually normal, whereas serum pepsinogen concentrations were invariably elevated. Serum parietal cell antibodies were not present. Acid secretion returned to near baseline levels in 14 of 17 subjects after a mean of 126 days (range 53--235); severity of gastritis diminished concurrently in 7 of 10 subjects on whom biopsies were serially performed. An infectious etiology is suspected, although serologic studies and bacterial and conventional viral cultures of stool and gastric juice have not identified a candidate agent.

Suppression and reversal of allergic encephalomyelitis in rhesus monkeys with basic protein and peptides

We have extended earlier studies on the suppression of clinically evident experimental allergic encephalomyelitis (EAE) in monkeys, repeated injections of human basis protein. The results confirm that after suppressive treatment, recovered animals remain clinically normal and do not show spontaneous recurrence of symptoms. However, recovered animals are susceptible to EAE upon renewed challenge, and they develop the disease more rapidly and more severely than after the initial challenge; resuppression is also accomplished in these cases by the same methods used previously. The results indicate further that the basic protein or peptide T administered without mycobacteria is effective in suppressing the development of basic protein-induced EAE regardless of the species from which it was derived.

Experimental allergic aspermatogenic orchitis. IV. Chemical properties of sperm glycoproteins isolated from guinea pig testes

Of four glycoproteins isolated from guinea pig testes, two were aspermatogenic (types I and IV) and two (types II and III) were inactive. The glycoproteins were rich in carbohydrate, varying from 41.5% to 49.5% carbohydrate by weight. Each glycoprotein had a unique amino acid composition, but in general low levels of tyrosine, tryptophan, and basic amino acids were found along with relatively high contents of serine, threonine, glutamic acid, and proline. Types I and IV glycoproteins were remarkably stable; their aspermatogenic activity was not affected by urea, trypsin, or heating at 100 degrees C in water or in 1 M HCl for 15 min. Carbohydrate analysis revealed little difference in the monosaccharide compositions of types I and IV glycoproteins, except that only the type I contained sialic acid. In contrast, types II and III glycoproteins lacked sialicacid and fucose and contained much less mannose. Both N-acetylglucosamine and N-acetylgalactosamine were present in all four glycoproteins, and they dominated in the types II and III. Fucose and at least 20-25% of the galactose appeared to occupy terminal positions in type IV glycoprotein as shown by their release after 15 min hydrolysis in 1 M HCl. All of the glycoproteins contained a relatively high percentage of galactose by weight, from 12.6 to 19.3%. The molecular weights of the glycoproteins were estimated by sodium dodecyl sulfate gel electrophoresis to be 47000, 105000 and 18000 respectively for the types I, II, and IV; type III glycoprotein showed two major bands, with molecular weights of 41500 and 22800. All the above molecular weight values are probably overestimated because of high carbohydrate content. The molecular weight of type IV glycoprotein was found to be 13000 by ultracentrifugation; a corrected value of 29000 was calculated for type I glycoprotein.

Experimental allergic aspermatogenic orchitis. II. Some chemical properties of the AP1 protein of the sperm acrosome

The AP1 protein, a unique aspermatogenic protein localized in the sperm acrosome, exists as a single polypeptide chain of 136 amino acids, as shown by a single band on gel electrophoresis in sodium dodecyl sulfate and the recovery of the expected 21 to 22 tryptic peptides on peptide mapping. The AP1 protein appears to exist in a compact, highly stable conformation, as shown by its resistance to trypsin hydrolysis. Its aspermatogenic acitivity is not affected by trypsin treatment, by heating at 99 degrees C for 1 h, by 8 M urea, or by acid conditions. After reduction and alkylation, however, the molecule appears to open up, since it becomes hydrolyzable by trypsin and migrates more slowly on gel electrophoresis at pH 2.7 and 8.6. After alkylation, the AP1 protein still migrates as a single band at pH 2.7. The AP1 protein shows microheterogeneity near its isolectric point at pH 8.6; each of five bands shows the same amino acid analysis. Aggregation was not observed following treatment with dimethylsuberimidate. The molecular weight of 15 000, obtained from gel electrophoresis consists of 136 amino acids with a relatively high content of proline, half cystine, glycine, histidine and tryptophan. No galactose, mannose, fucose, glucose, or hexosamines were found; the AP1 protein is thus not a glycoprotein.

Experimental allergic orchitis and aspermatogenesis. VI. Transfer of allergic orchitis with immune cells

Typical experimental allergic orchitis (EAO) and aspermatogenesis were successfully transferred to strain 13 guinea pigs with peritoneal exudate and lymph node cells from male and female donor guinea pigs (lacking detectable antibody) previously sensitized with 9 mug of highly purified GP1 glucoprotein isolated from the sperm acrosome. Attempts to transfer the disease with circulating antibody from hyperimmunized animals were not successful. These studies support a cell-mediated basis for the immunopathologic events in EAO.

Experimental allergic aspermatogenic orchitis. III. Isolation of spermatozoal glycoproteins and their role in allergic aspermatogenic orchitis

Four glycoproteins (GP1,2,3 and 4) rich in carbohydrate were isolated from guinea pig testes. GP1, 2, and 4 (one or more) were localized in the sperm acrosome by the indirect immunofluorescence technique. Purification consisted of delipidation with chloroform-methanol (2:1), acid extraction at pH 3.0, precipitation with 85% saturated ammonium sulfate, extraction with 5% trichloroacetic acid, and either gel filtration on agarose or ultrafiltration. The final purification steps were isoelectrofocusing or gel filtration on Sephadex G-75 followed by preparative slab gel electrophoresis at pH 8.6. Each glycoprotein appeared homogeneous by gel electrophoresis at pH 2.7 and 8.6, and by immunoelectrophoresis. The crude glycoprotein fraction from the agarose column was resolved into the three major components, GP1, 2, and 3, distinguished by their isoelectric points (pI 3.9, 4.4, and 5.0, respectively), electrophoretic mobilities at pH 8.6, and reactivities with antiserum in immunoelectrophoresis. GP4, isolated by ultrafiltration and Sephadex G-75 chromatography, was differentiated by the same criteria. Approximately 5 mg each of purified GP1, 3, and 4 and 2 to 3 mg of GP2 were isolated from 1000 g of wet guinea pig testes. GP1, 2, and 4 induced precipitating antibody in rabbits and goats. GP1 and GP4 induced allergic aspermatogenic orchitis in guinea pigs, an autoimmune disease characterized by infiltration of mononuclear cells around and within the seminiferous tubules, followed by extensive destruction of the germinal epithelium. The course of the disease induced by 2 mug of either GP1 or GP4 was essentially identical in time course and pathology to that induced by whole testicular homogenates or 1 mug of purified acrosomal protein (AP1).

Experimental allergic aspermatogenic orchitis. 1. Isolation of a spermatozoal protein (AP1) which induces allergic aspermatogenic orchitis

A unique highly soluble aspermatogenic protein (AP1) was isolated from guinea pig testes and was shown by immunofluorescence to occupy the outer surface of the sperm acrosome. This protein is a potent inducer of allergic orchitis and aspermatogenesis; as little as 0.2 mug induced orchitis in 60 percent of guinea pig tested. The AP1 protein, relatively small and neutral, is stable under acid conditions, but at pH 8.6 shows a variety of forms due either to aggregation or polymorphism. The purified AP1 protein appeared homogeneous by polyacrylamide gel electrophoresis at pH 2.7 and in sodium dodecyl sulfate and by immunoelectrophoresis using rabbit antisera to either the purified protein or the testes extract. It also showed a single band on immunodiffusion over a wide concentration range. The purification procedure consisted of delipidation with chloroform/methanol (2/1); acid extraction at pH 3.0; precipitation with 85 percent saturated ammonium sulfate; trichloroacetic acid extraction and gel filtration on Bio-Gel A-1.5; gel filtration on Bio-Gel P-10; chromatography on CM52 cellulose; and preparative gel electrophoresis at pH 2.7. Approximately 20 mg of purified AP1 protein were obtained from 5000 g of wet guinea pig testes. The AP1 protein induced an autoimmune disease characterized by infiltration of mononuclear cells around and within the seminiferous tubules (orchitis), followed by extensive damage and destruction of the germinal cells (aspermatogenesis). The course of the disease induced by this protein (0.5 to 1 mug) was essentially identical with that seen with whole testicular tissue or other purified fractions.